The parameters investigated were mass temperature
(110, 130 or 150 °C), moisture content (200 or 300 g/kg) of the diets
prior to extrusion and number of times (once or twice) extruded. Total lysine
and other amino acids were unaffected by the extrusion conditions employed.
Extrusion conditions had a clear effect on the reactive lysine content with the
ratio of reactive to total lysine increasing from 0.71 to 0.80 and higher as a
result of extrusion and temperature. After a second extrusion, a decrease was
observed from a ratio reaching 1.0 to about 0.9. Initial moisture content
affected lysine reactivity. Protein digestibility as measured in vitro
was not affected by different extruding conditions.
There were no obvious differences in protein dispersibility index (PDI) of all the extrudates. In vitro glucose digestibility coefficients as well as starch gelatinization degree (SGD) showed a tendency to increase with an increase in each individual parameter tested. The increase in temperature from 110 to 150 °C as well as extrusion for a second time decreased kibble durability while increasing moisture content increased durability. Optimisation of extrusion conditions during commercial pet food production should include measurement of the reactive to total lysine ratio.
Related websites:
Wageningen University
TNO
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There were no obvious differences in protein dispersibility index (PDI) of all the extrudates. In vitro glucose digestibility coefficients as well as starch gelatinization degree (SGD) showed a tendency to increase with an increase in each individual parameter tested. The increase in temperature from 110 to 150 °C as well as extrusion for a second time decreased kibble durability while increasing moisture content increased durability. Optimisation of extrusion conditions during commercial pet food production should include measurement of the reactive to total lysine ratio.
Related websites:
Wageningen University
TNO
To receive more animal feed news, subscribe here
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